The Heart |
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The heart is comprised of four chambers. The left and right
atria are the two upper chambers and the left and right ventricles
are the lower chambers. The left ventricle is the largest
chamber.
Four heart valves open and close
so that blood only flows through the heart in one direction.
The four valves include the tricuspid valve, pulmonary valve,
mitral valve, and the aortic valve.
The pulmonary arteries and veins connect the heart to the
lungs.
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Blood from the body enters the right atrium of the heart.
Blood from the body is low in oxygen and must gather oxygen
before returning to the rest of the body. Blood passes from
the right atria through the tricuspid valve into the right
ventricle. Blood is then pumped through the pulmonary valve
into the pulmonary artery where it travels to the lungs to
gather oxygen.
Blood returns from the lungs in the
pulmonary veins where it enters the left atrium of the heart.
Blood passes from the left atria through the mitral valve
into the left ventricle. The left ventricle pumps blood through
the aortic valve into the aorta. From the aorta, blood rich
in oxygen travels to the rest of the body. Eventually blood
from the body returns to the heart to gather new oxygen.
The heart works most efficiently
when blood that lacks oxygen is separated from blood that
is rich in oxygen.
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Congenital Heart Defects |
Septal Defects
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Atrial Septal Defect (ASD)
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An atrial septal defect (ASD) is an abnormal hole or defect
in the wall that separates the left and right atria. Blood
rich in oxygen mixes with blood that lacks oxygen. As a result,
the heart pumps some blood that lacks oxygen to the body.
Likewise, the heart pumps some blood rich in oxygen to the
lungs. As a result, the heart does not work efficiently.
Many children with an ASD have few
symptoms or concerns. Most often, the hole closes over time.
Some children need to have the hole or defect surgically repaired.
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Atrioventricular (AV) Canal
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An atrioventricular (AV) canal is a large defect in the wall
the separates the upper heart chambers from the lower heart
chambers. In addition, the tricuspid and mitral valves do
not form properly.
This defect results in a mixture
of blood rich in oxygen with blood that lacks oxygen. As a
result, most children with this heart defect do not grow well
and many children have symptoms early in life.
Surgery is always required to repair
an AV canal. The atrioventricular canal defect is the most
common heart defect identified for children with Down syndrome.
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Ventricular Septal Defect (VSD)
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A ventricular septal defect (VSD) is an abnormal hole or
defect in the wall that separates the left and right ventricle.
Blood rich in oxygen mixes with blood that lacks oxygen. As
a result, the heart pumps some blood that lacks oxygen to
the body. Likewise, the heart pumps some blood rich in oxygen
to the lungs. As a result, the heart does not work efficiently.
Sometimes the VSD closes over time.
However, for other children, the defect is too large and surgical
repair of the defect is necessary.
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Blood Vessel Defects
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Aortic stenosis
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Aortic stenosis is a constriction or narrowing of the aortic
valve. The aortic valve allows blood to pass from the left
ventricle to the aorta. Narrowing of the aortic valve forces
the left ventricle to work harder.
Aortic stenosis may be able to be
corrected during cardiac catheterization using a technique
known as a balloon valvuloplasty. Some children may require
surgery to correct or replace the aortic valve.
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Coarctation of the aorta
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Coarctation of the aorta is a constriction of part of the
aorta. Blood cannot pass freely from the heart to the rest
of the body. As a result, the blood pressure increases before
the point of the constriction. Blood rich in oxygen cannot
easily flow to the rest of the body.
Coarctation of the aorta must be
surgically repaired, but the heart does not need to be opened
during the surgery. Coarctation of the aorta is the most common
heart defect in girls with Turner syndrome.
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Pulmonary stenosis
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Pulmonary stenosis is a constriction or narrowing of the
pulmonary valve. The pulmonary valve allows blood to pass
from the right ventricle to the lungs. Narrowing of the pulmonary
valve forces the right ventricle to work harder.
Pulmonary stenosis may be able to
be corrected during cardiac catheterization using a technique
known as a balloon valvuloplasty.
Pulmonary stenosis is the most common
heart defect associated with Williams syndrome.
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Cyanotic Heart Defects
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Hypoplastic left heart syndrome
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Hypoplastic left heart syndrome is a condition in which the
left side of the heart, including the aorta, aortic valve,
left ventricle and mitral valve are underdeveloped. As a result,
blood rich in oxygen cannot be pumped to the body.
Unless treated, hypoplastic left
heart syndrome results in premature death in the first few
weeks of life. Several surgeries over time are required to
repair the heart defect. Some children undergo a heart transplant.
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Tetralogy of Fallot
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Tetralogy of Fallot involves four separate changes in the
structure of the heart. These changes include:
- Ventricular septal defect
- Pulmonary stenosis
- Overriding aorta
- Hypertrophy (enlargement) of the right ventricle.
Tetralogy of Fallot is a type of cyanotic heart defect in
which the body does not receive enough blood rich in oxygen.
Surgery is required to fix the defects
associated with Tetralogy of Fallot. It is not uncommon that
children require more than one type of surgery.
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Transposition of the great arteries
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Transposition of the great arteries results when the pulmonary
artery and the aorta are reversed from their point of origin.
The aorta is connected to the right ventricle and thus it
carries blood that lacks oxygen to the body. The pulmonary
artery is connected to left ventricle and thus it carrier
blood rich in oxygen back to the lungs.
Surgery is required to correct the
transposition of the great arteries. Surgery may be required
soon after birth if the child does not receive sufficient
oxygen.
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Truncus arteriosus
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Truncus arteriosus is a defect in which only one artery arises
from the heart to form both the aorta and the pulmonary artery.
Typically, these two vessels are separated from one another.
There is a mixture of blood rich in oxygen with blood that
lacks oxygen.
Children with truncus arteriosus
generally require heart surgery early in life. Truncus arteriosus
is the most common heart defect among children with DiGeorge
syndrome.
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Other Heart Defects
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Patent ductus arteriosus (PDA)
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The ductus arteriosus is a normal opening between the pulmonary
artery and the aorta. Every child is born with a ductus arteriosus.
The ductus arteriosus typically closes a few hours after birth.
If it does not close, it is known as a patent ductus arteriosus.
Many premature babies have a patent
ductus arteriosus. Some children need surgery to correct the
heart problem, however the heart does not have to be opened
in order to correct a patent ductus arteriosus.
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